IPY: A Community Genomics Investigation of Fungal Adaptation to Cold

这项研究将对北极地区的真菌进行大规模的群落基因组分析，以深入了解适应寒冷的真菌的多样性、新陈代谢和季节动态。真菌在极端寒冷、通常干燥和大部分被雪覆盖的北极土壤中生存、繁殖和进行各种生物地球化学转化。显然，这些真菌适应极端的寒冷和黑暗。然而，我们对这些适应寒冷的真菌的身份和活动的了解微不足道。这项工作的目标是更好地了解真菌对寒冷的适应，并将通过确定哪些物种出现在最冷的气候中，以及哪些物种在最冷的温度下代谢活跃来实现这一点。在专注于适应的同时，该项目还将向生态系统生态学提供信息。极地地区为社会提供重要的生态系统服务，包括气候调节。极地地区的持续变化往往比低纬度地区更快、幅度更大，对生态系统服务产生了不确定的影响，特别是对全球变暖的积极和消极反馈。两个相互关联的关键不确定性是1)植被模式将如何变化，以及这些变化将如何反馈给气候，以及2)土壤碳库将如何随着永冻土、土壤温度和植被覆盖模式的变化而变化。菌根真菌通过其作为北极植物普遍存在的共生体的作用，对植物的生长和群落结构产生重要影响。分解真菌强烈影响呼吸碳向大气释放的速率和模式，以及限制营养物质氮和磷的矿化和固定。因此，土壤真菌是植被变化和碳动态的核心角色，因此，关于真菌在极地生态系统中作用的不确定性导致了对气候变化和极地地区未来的总体不确定性。研究中提出的三个具体目标是：(1)通过使用高通量、基于DNA的克隆文库测序来表征真菌群落沿三个纬度梯度(NAAT、欧亚大陆、斯匹茨卑尔根)的变化，揭示哪些真菌物种最适应北极极端环境条件；(2)利用图利克湖和Bonanza Creek长期生态研究(LTER)地点的相互土壤变暖和降温实验以及克隆文库测序，测试预测的气候变化是否会选择更南端或更北端的真菌群落；以及(3)使用新开发的基于RNA的文库测序方法来表征在夏季和冬季代谢活跃的真菌群落的成分。通过揭示哪些真菌物种和协会在不同的生境、不同的季节和不同的温度条件下最活跃，这项工作将揭示对北极冬季呼吸和养分循环过程的新见解。这项研究是泛北极的和国际的，无论是在地理范围上，还是在美国、俄罗斯和英国科学家的合作联盟中。在地方一级，它将教育小学生关于真菌及其生态学的知识，并将支持多个国家之间的研究生教育和科学交流。

IPY FY 06 Life in the Cold and Dark ARC- 0632332 TaylorThis research will conduct a large-scale community genomics analysis of fungi in the Arctic to provide insights into the diversity, metabolism, and seasonal dynamics of cold-adapted fungi. Fungi survive, reproduce, and carry out diverse biogeochemical transformations in arctic soils that are extremely cold, often dry, and mostly snow covered. Clearly, these fungi are adapted to extremes of cold and dark. Yet our knowledge of the identities and activities of these cold-adapted fungi is negligible. The goal of this work is to better understand fungal adaptation to cold, and will accomplish this by determining which species occur in the coldest climates, and which species are metabolically active at the coldest temperatures. While focused on adaptation, the project will also inform ecosystem ecology. Polar regions provide significant ecosystem services to society, including climate regulation. The ongoing changes in polar regions, which are often more rapid and of larger magnitude than in lower latitudes, are having uncertain effects on ecosystem services, particularly positive and negative feedbacks to global warming. Two key, interrelated uncertainties are 1) how vegetation patterns will change, and how these changes will feed back to climate, and 2) how soil carbon pools will change with changing patterns of permafrost, soil temperatures and vegetation cover. Mycorrhizal fungi strongly influence plant growth and community structure through their roles as ubiquitous symbionts of arctic plants. Decomposer fungi strongly influence rates and patterns of respiratory carbon release to the atmosphere, as well as mineralization and immobilization of the limiting nutrients nitrogen and phosphorus. Hence, soil-dwelling fungi are central players in both vegetation change and carbon dynamics, and therefore, uncertainties about the roles of fungi in polar ecosystem contribute to overall uncertainties about climate change and the future of polar regions. The three specific objectives in the research proposed are to: (1) reveal which fungal species are most adapted to extreme arctic environmental conditions by characterizing the changes in fungal communities along three latitudinal gradients (NAAT, Eurasia, Spitsbergen) using high-throughput, DNA-based clone-library sequencing; (2) test whether predicted changes in climate will select for more southerly or northerly fungal communities using reciprocal soil warming and cooling experiments and clone-library sequencing at the Toolik Lake and Bonanza Creek Long Term Ecological Research (LTER) sites; and (3) characterize the components of the fungal communities that are metabolically active in both summer and winter using a newly developed RNA-based library sequencing method. By revealing which species and guilds of fungi are most active in different habitats, in different seasons, and under different temperature regimes, the work will unveil novel insights into processes underling winter respiration and nutrient cycling in the Arctic. The study is pan-Arctic and international, both in geographic extent and in the collaborating consortium of US, Russian, and UK scientists. At the local level it will educate elementary school students about fungi and their ecology, and will support graduate education and scientific exchange among multiple countries.